270 research outputs found

    Particle-Number Projected Hartree-Fock-Bogoliubov Study with Effective Shell Model Interactions

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    We perform particle-number projected mean-field study using the recently developed symmetry-projected Hartree-Fock-Bogoliubov (HFB) equations. Realistic calculations have been performed in sd- and fp-shell nuclei using the shell model empirical intearctions, USD and GXPFIA. It is demonstrated that the mean-field results for energy surfaces, obtained with these shell model interactions, are quite similar to those obtained using the density functional approaches. Further, it is shown that particle-number projected results, for neutron rich isotopes, can lead to different ground-state shapes in comparison to the bare HFB calculations.Comment: 10 page

    Investigation of structural and optoelectronic properties of BaThO3

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    Structural and optoelectronic properties of BaThO3 cubic perovskite are calculated using all electrons full potential linearized augmented plane wave (FP-LAPW) method. Wide and direct band gap, 5.7 eV, of the compound predicts that it can be effectively used in UV based optoelectronic devices. Different characteristic peaks in the wide UV range emerges mainly due to the transition of electrons between valance band state O-p and conduction band states Ba-d, Ba-f, Th-f and Th-d.Comment: 20 pages and 7 figure

    Enhanced Heartbeat Graph for emerging event detection on Twitter using time series networks

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    ยฉ 2019 Elsevier Ltd With increasing popularity of social media, Twitter has become one of the leading platforms to report events in real-time. Detecting events from Twitter stream requires complex techniques. Event-related trending topics consist of a group of words which successfully detect and identify events. Event detection techniques must be scalable and robust, so that they can deal with the huge volume and noise associated with social media. Existing event detection methods mostly rely on burstiness, mainly the frequency of words and their co-occurrences. However, burstiness sometimes dominates other relevant details in the data which could be equally significant. Besides, the topological and temporal relationships in the data are often ignored. In this work, we propose a novel graph-based approach, called the Enhanced Heartbeat Graph (EHG), which detects events efficiently. EHG suppresses dominating topics in the subsequent data stream, after their first detection. Experimental results on three real-world datasets (i.e., Football Association Challenge Cup Final, Super Tuesday, and the US Election 2012) show superior performance of the proposed approach in comparison to the state-of-the-art techniques

    Portable haptic device for lower limb amputee gait feedback: assessing static and dynamic perceptibility

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    Loss of joints and severed sensory pathway cause reduced mobility capabilities in lower limb amputees. Although prosthetic devices attempt to restore normal mobility functions, lack of awareness and control of limb placement increase the risk of falling and causing amputee to have high level of visual dependency. Haptic feedback can serve as a cue for gait events during ambulation thus providing sense of awareness of the limb position. This paper presents a wireless wearable skin stretch haptic device to be fitted around the thigh region. The movement profile of the device was characterized and a preliminary work with able-bodied participants and an above-knee amputee to assess the ability of users to perceive the delivered stimuli during static and dynamic mode is reported. Perceptibility was found to be increasing with stretch magnitude. It was observed that a higher magnitude of stretch was needed for the stimuli to be accurately perceived during walking in comparison to static standing, most likely due to the intense movement of the muscle and increased motor skills demand during walking activity

    Physico-Chemical Characterization Of Sweet Chestnut (Castanea Sativa L.) Starch Grown In Temperate Climate Of Kashmir, India

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    Studies were conducted to characterize the chestnut starch for physico-chemical properties. Chemical composition of chestnut starch showed low levels of protein and ash indicating purity of starch. The results revealed low water and oil absorption capacity of chestnut starch. Starch showed high swelling power and low solubility index. Swelling power and solubility index of chestnut starch increased with increase in temperature (50โ€“90 ยฐC). The results revealed high initial, peak, setback, breakdown, and final viscosity but low paste development temperature. Transmittance (%) of the starch gel was low and decreased with increasing storage period. The chestnut starch gel showed increase in % water release (syneresis) with increase in time of storage but was less susceptible to repeated cycles of freezing and thawing. Starch was also characterized for granule morphology. Starch granules were of round and oval shapes, some granules showed irregular shape

    High-Spin Doublet Band Structures in odd-odd 194โˆ’200^{194-200}Tl isotopes

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    The basis space in the triaxial projected shell model (TPSM) approach is generalized for odd-odd nuclei to include two-neutron and two-proton configurations on the basic one-neutron coupled to one-proton quasiparticle state. The generalization allows to investigate odd-odd nuclei beyond the band crossing region and as a first application of this development, high-spin band structures recently observed in odd-odd 194โˆ’200^{194-200}Tl isotopes are investigated. In some of these isotopes, the doublet band structures observed after the band crossing have been conjectured to arise from the spontaneous breaking of the chiral symmetry. The driving configuration of the chiral symmetry in these odd-odd isotopes is one-proton and three-neutrons rather than the basic one-proton and one-neutron as already observed in many other nuclei. It is demonstrated using the TPSM approach that energy differences of the doublet bands in 194^{194}Tl and 198^{198}Tl are, indeed, small. However, the differences in the calculated transition probabilities are somewhat larger than what is expected in the chiral symmetry limit. Experimental data on the transition probabilities is needed to shed light on the chiral nature of the doublet bands.Comment: 11 pages, 17 figures, to appear in EPJ

    Whatโ€™s Happening Around the World? A Survey and Framework on Event Detection Techniques on Twitter

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    ยฉ 2019, Springer Nature B.V. In the last few years, Twitter has become a popular platform for sharing opinions, experiences, news, and views in real-time. Twitter presents an interesting opportunity for detecting events happening around the world. The content (tweets) published on Twitter are short and pose diverse challenges for detecting and interpreting event-related information. This article provides insights into ongoing research and helps in understanding recent research trends and techniques used for event detection using Twitter data. We classify techniques and methodologies according to event types, orientation of content, event detection tasks, their evaluation, and common practices. We highlight the limitations of existing techniques and accordingly propose solutions to address the shortcomings. We propose a framework called EDoT based on the research trends, common practices, and techniques used for detecting events on Twitter. EDoT can serve as a guideline for developing event detection methods, especially for researchers who are new in this area. We also describe and compare data collection techniques, the effectiveness and shortcomings of various Twitter and non-Twitter-based features, and discuss various evaluation measures and benchmarking methodologies. Finally, we discuss the trends, limitations, and future directions for detecting events on Twitter

    Antibacterial Composite Materials Based on the Combination of Polyhydroxyalkanoates With Selenium and Strontium Co-substituted Hydroxyapatite for Bone Regeneration.

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    Due to the threat posed by the rapid growth in the resistance of microbial species to antibiotics, there is an urgent need to develop novel materials for biomedical applications capable of providing antibacterial properties without the use of such drugs. Bone healing represents one of the applications with the highest risk of postoperative infections, with potential serious complications in case of bacterial contaminations. Therefore, tissue engineering approaches aiming at the regeneration of bone tissue should be based on the use of materials possessing antibacterial properties alongside with biological and functional characteristics. In this study, we investigated the combination of polyhydroxyalkanoates (PHAs) with a novel antimicrobial hydroxyapatite (HA) containing selenium and strontium. Strontium was chosen for its well-known osteoinductive properties, while selenium is an emerging element investigated for its multi-functional activity as an antimicrobial and anticancer agent. Successful incorporation of such ions in the HA structure was obtained. Antibacterial activity against Staphylococcus aureus 6538P and Escherichia coli 8739 was confirmed for co-substituted HA in the powder form. Polymer-matrix composites based on two types of PHAs, P(3HB) and P(3HO-co-3HD-co-3HDD), were prepared by the incorporation of the developed antibacterial HA. An in-depth characterization of the composite materials was conducted to evaluate the effect of the filler on the physicochemical, thermal, and mechanical properties of the films. In vitro antibacterial testing showed that the composite samples induce a high reduction of the number of S. aureus 6538P and E. coli 8739 bacterial cells cultured on the surface of the materials. The films are also capable of releasing active ions which inhibited the growth of both Gram-positive and Gram-negative bacteria

    Antibacterial Composite Materials Based on the Combination of Polyhydroxyalkanoates With Selenium and Strontium Co-substituted Hydroxyapatite for Bone Regeneration

    Get PDF
    Due to the threat posed by the rapid growth in the resistance of microbial species to antibiotics, there is an urgent need to develop novel materials for biomedical applications capable of providing antibacterial properties without the use of such drugs. Bone healing represents one of the applications with the highest risk of postoperative infections, with potential serious complications in case of bacterial contaminations. Therefore, tissue engineering approaches aiming at the regeneration of bone tissue should be based on the use of materials possessing antibacterial properties alongside with biological and functional characteristics. In this study, we investigated the combination of polyhydroxyalkanoates (PHAs) with a novel antimicrobial hydroxyapatite (HA) containing selenium and strontium. Strontium was chosen for its well-known osteoinductive properties, while selenium is an emerging element investigated for its multi-functional activity as an antimicrobial and anticancer agent. Successful incorporation of such ions in the HA structure was obtained. Antibacterial activity against Staphylococcus aureus 6538P and Escherichia coli 8739 was confirmed for co-substituted HA in the powder form. Polymer-matrix composites based on two types of PHAs, P(3HB) and P(3HO-co-3HD-co-3HDD), were prepared by the incorporation of the developed antibacterial HA. An in-depth characterization of the composite materials was conducted to evaluate the effect of the filler on the physicochemical, thermal, and mechanical properties of the films. In vitro antibacterial testing showed that the composite samples induce a high reduction of the number of S. aureus 6538P and E. coli 8739 bacterial cells cultured on the surface of the materials. The films are also capable of releasing active ions which inhibited the growth of both Gram-positive and Gram-negative bacteria

    Antibacterial Composite Materials Based on the Combination of Polyhydroxyalkanoates With Selenium and Strontium Co-substituted Hydroxyapatite for Bone Regeneration

    Get PDF
    Due to the threat posed by the rapid growth in the resistance of microbial species to antibiotics, there is an urgent need to develop novel materials for biomedical applications capable of providing antibacterial properties without the use of such drugs. Bone healing represents one of the applications with the highest risk of postoperative infections, with potential serious complications in case of bacterial contaminations. Therefore, tissue engineering approaches aiming at the regeneration of bone tissue should be based on the use of materials possessing antibacterial properties alongside with biological and functional characteristics. In this study, we investigated the combination of polyhydroxyalkanoates (PHAs) with a novel antimicrobial hydroxyapatite (HA) containing selenium and strontium. Strontium was chosen for its well-known osteoinductive properties, while selenium is an emerging element investigated for its multi-functional activity as an antimicrobial and anticancer agent. Successful incorporation of such ions in the HA structure was obtained. Antibacterial activity against Staphylococcus aureus 6538P and Escherichia coli 8739 was confirmed for co-substituted HA in the powder form. Polymer-matrix composites based on two types of PHAs, P(3HB) and P(3HO-co-3HD-co-3HDD), were prepared by the incorporation of the developed antibacterial HA. An in-depth characterization of the composite materials was conducted to evaluate the effect of the filler on the physicochemical, thermal, and mechanical properties of the films. In vitro antibacterial testing showed that the composite samples induce a high reduction of the number of S. aureus 6538P and E. coli 8739 bacterial cells cultured on the surface of the materials. The films are also capable of releasing active ions which inhibited the growth of both Gram-positive and Gram-negative bacteria
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